1, the land area of China is about 9.6 million km.

2. A number consists of 2.3 billion, 605 million and 78 ones. This number is written as ().

3. The product of the largest three digits multiplied by the smallest two digits is ().

4. In 5□890≈60000, □ can be filled in at most () and at least ().

5. The ground floor of a building is the first floor, and the elevator sign on 17 floor is marked as (); The second floor underground is marked as ().

6. fill in ">,